CN101924972A

CN101924972A - Signal processing apparatus and signal processing method

Info

Publication number: CN101924972A
Application number: CN2010101982061A
Authority: CN
Inventors: 米田道昭; 仲上太郎
Original assignee: Sony Corp
Current assignee: Sony Corp
Priority date: 2009-06-12
Filing date: 2010-06-04
Publication date: 2010-12-22
Anticipated expiration: 2030-06-04
Also published as: US20100316226A1; CN101924972B; US8761408B2; JP2010288119A; JP5321263B2

Abstract

A signal processing apparatus includes: one or more detection means for detecting movement of a diaphragm of a speaker in correspondence with feedback methods that are different feedback methods; analog-to-digital conversion means for converting one or more detection signals acquired by the detection means into a digital form; feedback signal generating means for generating feedback signals corresponding to the feedback methods using the digital detection signals; synthesis means for combining an audio signal to be output as a driving signal of the speaker with the feedback signals; correction equalizer means for setting an equalizing characteristic to allow a sound reproduced by the speaker to have a target frequency characteristic by changing the digital audio signal; feedback operation setting means for setting feedback methods in which a feedback operation up to combining the audio signal with the feedback signal is performed and the feedback operation is not performed equalizing characteristic changing and setting means for changing the equalizing characteristic to be set by the correction equalizer means in accordance with a combination of the feedback methods.

Description

Signal handling equipment and signal processing method

Technical field

The present invention relates to according to predetermined purpose is signal handling equipment and the method thereof that audio signal is carried out signal processing.

Background technology

In field of acoustics, MFB (motion feedback) is known.MFB is used for the motion of the vibrating membrane by detecting loudspeaker unit and applies negative feedback to the audio signal of input, comes the vibrating membrane of control example such as loudspeaker unit and the audio signal of input to have identical motion.Therefore, for example near the vibration low band resonant frequency f0 is attenuated, thereby is acoustically being suppressed such as the undesirable influence to low-frequency band of so-called " buzz " (boomy base).

Correlation technique is open in JP-A-9-289699.

Summary of the invention

So far, the MFB technology only is used to strengthen the quality from the sound of loudspeaker unit reproduction.Need give new value-added functionality by the MFB technology to provide more useful voice frequency listening environment for for example user as the hearer.

According to one embodiment of present invention, provide a kind of signal handling equipment, comprising: one or more checkout gears, arrange to be used for according to detecting the motion of the vibrating membrane of loud speaker to the n feedback method as first of different feedback methods; Analog-digital commutator, the one or more detection signals that are used for analog form that checkout gear is obtained are converted to digital form; Feedback signal generating means is used for generating corresponding to first feedback signal to the n feedback method by the detection signal that utilizes the digital form that analog-digital commutator obtains; Synthesizer is used for being output as the audio signal and the feedback signal combination of digital form of the drive signal of loud speaker; The correcting balancer device is used to be provided with the frequency characteristic of equalization characteristic with the audio signal by changing digital form, makes that the sound by loudspeaker reproduction has target frequency characteristic; The feedback operation setting device is used for from first to the n feedback method feedback method wherein carry out the feedback operation of being carried out by synthesizer that audio signal and feedback signal are made up and the feedback method of wherein not carrying out feedback operation being set; And equalization characteristic changes and setting device, and being used for will be by the equalization characteristic of correcting balancer device setting according to wherein being changed by the feedback method of the set execution feedback operation of feedback operation setting device and the combination of wherein not carrying out the feedback method of feedback operation.

Under above-mentioned configuration, dispose at least one based on Digital Signal Processing (digital circuit) and be used for generating feedback signal and applying the system of feedback signal, as MFB (moving feedback) signal processing system as feedback to the audio signal of importing based on detection signal.In addition, as one embodiment of the present of invention, concentrate on based on Digital Signal Processing and realize changing inner setting easily, change parameter or the like, the combination of the feedback method of will be opened from a plurality of feedback methods (turn on) is configured to and can be changed.In addition, according to the change of the combination of the feedback method that will be opened, the equalization characteristic that is used for proofreading and correct the frequency characteristic of the sound that loud speaker reproduces also is changed.

Therefore, according to embodiments of the invention, for example by changing the combination of the feedback method that will be opened, can be based on whether having used the reproduction sound that MFB selects to have different listen mode.In addition, thus, the frequency characteristic of reproducing sound is suitably corrected according to the combination of the feedback method that will be opened.In other words, with the feedback method that is opened, can obtain best frequency characteristic by combination, thereby the sound quality of reproducing sound can be held fabulous.

As mentioned above,, can propose a kind of new sound and listen to method, wherein can select combination according to feedback method to sound difference on the different reproduction sound, keep reproducing the splendid sound quality of sound simultaneously according to embodiments of the invention.

Description of drawings

Fig. 1 shows an example by the basic configuration of the MFB signal processing system of digital circuit configuration;

Fig. 2 shows according to present embodiment, by a profile instance of the MFB signal processing system of digital circuit configuration;

Fig. 3 is illustrated in the pattern of MFB-pass, the frequency characteristic of the sound that is reproduced by loudspeaker unit;

Fig. 4 is illustrated in the MFB-on-mode, the frequency characteristic of the sound that is reproduced by loudspeaker unit;

Fig. 5 is illustrated in the frequency characteristic of the sound that is reproduced by loudspeaker unit in the 2nd MFB-on-mode;

Fig. 6 is illustrated in the MFB-on-mode and carries out under the situation that equalizer proofreaies and correct, the frequency characteristic of the sound that is reproduced by loudspeaker unit;

Fig. 7 A-7C illustrated based on transient phenomenon, corresponding to the difference of the sound of each MFB operator scheme;

Fig. 8 represents the example of the content of mode setting table;

Fig. 9 represents to gain-example of the content of correcting feature table;

Figure 10 shows a profile instance of revising the MFB signal processing system of example according to present embodiment;

Figure 11 shows according to an embodiment, is used to be provided with the profile instance of the digital signal processing unit of feedback oscillator;

Figure 12 shows according to an embodiment, is used to be provided with the profile instance of the digital signal processing unit of equalizer correcting feature;

Figure 13 is a flow chart, and expression is provided with the example of the processing sequence of equalizer correcting feature based on configuration shown in Figure 12;

Figure 14 shows according to an embodiment, is used to be provided with the profile instance of the initial equalizer correcting feature when dispatching from the factory shipment;

Figure 15 shows the profile instance of simulation MFB signal processing system;

Figure 16 shows under the situation of closing MFB signal processing system shown in Figure 15, the frequency characteristic of the sound that is reproduced by loudspeaker unit;

Figure 17 shows under the situation of opening MFB signal processing system shown in Figure 15, the frequency characteristic of the sound that is reproduced by loudspeaker unit;

Figure 18 shows by proofreading and correct the frequency characteristic that characteristic shown in Figure 17 is obtained;

Figure 19 shows the profile instance of the simulation MFB signal processing system that wherein can adjust feedback oscillator;

Figure 20 shows in MFB signal processing system shown in Figure 19, the example of the circuit form that forms according to the adjustment of feedback oscillator; And

Figure 21 is used to illustrate the frequency characteristic figure of example of adjustment of feedback oscillator of circuit form shown in Figure 20.

Embodiment

Describe in the following sequence below and be used to realize pattern of the present invention (hereinafter being called embodiment).

1. simulate the profile instance of MFB

2. digital MFB: basic configuration

3. digital MFB: embodiment

3-1. profile instance

3-2. the correcting feature of equalizer is set

3-3. application example (first example)

3-4. application example (second example)

4. digital MFB: revise example

5. the adjustment of feedback oscillator;

5-1. the adjustment in the analog circuit;

5-2. the adjustment in the digital circuit;

6. the adjustment of the correcting feature of equalizer;

6-1. the adjustment in the analog circuit;

6-2. the adjustment in the digital circuit;

1. simulate the profile instance of MFB

MFB (motion feedback) is used to detect the vibration of loudspeaker unit and applies degenerative technology to the audio signal that will be provided for loudspeaker unit.So far, made great efforts by using MFB control loudspeaker unit to vibrate the raising that realizes the sound quality heard according to the audio signal of input more accurately.Particularly, the unnecessary vibration of the vibrating membrane of loudspeaker unit, for example near the vibration low band resonant frequency f0 is suppressed.Therefore, can obtain the repressed sound of undesirable influence (so-called " buzz ") to low-frequency band.

Example under the situation that the signal processing system (MFB signal processing system) corresponding to MFB that shows Figure 15 is disposed by analog circuit.As shown in the figure, at first carry out the low-frequency band compensation that hereinafter will describe for simulated audio signal, and the audio signal output after will compensating is to synthesizer 102 by low-band correction equalizer 101.

Synthesizer 102 receive the audio signal that sends from low-band correction equalizer 101 and from the amount of gain adjustment unit 108 signals that transmit as input.108 signals that transmit from the amount of gain adjustment unit that hereinafter will describe are based on the detection of motion of loudspeaker unit 104 and the feedback signal of the MFB that obtains.Synthesizer 102 will be from the audio signal and the reverse feedback signal combination of low-band correction equalizer 101 transmission.In other words, come output audio signal by utilizing feedback signal to apply negative feedback to audio signal.

Amplified by power amplifier 103 and be output to loudspeaker unit 104 from the audio signal of equalizer 102 output.Therefore, in loudspeaker unit 104, reproduce sound according to audio signal.

Be disposed in from power amplifier 103 according to MFB by the bridgt circuit 105 of resistor R 1, R2 and R3 configuration and extend on the drive signal line of loudspeaker unit 104, and the output of bridgt circuit 105 is configured to be input to detector/amplifier circuit 106.

The signal that detector/amplifier circuit 106 amplifies by detecting after the signal that back electromotive force obtained that generates in the voice loop of loudspeaker unit 104 also will amplify outputs to low pass filter (LPF) 107.At this, the back electromotive force that is detected by bridgt circuit 105 is corresponding to the speed according to the motion detection vibrating membrane of the vibrating membrane of loudspeaker unit 104.

LPF107 removes frequency band unnecessary for MFB control and input signal is outputed to amount of gain adjustment unit 108 from input signal.

Amount of gain adjustment unit 108 is for example according to applying gain (feedback oscillator) and consequential signal is outputed to synthesizer 102 as feedback signal for the yield value of input signal setting in advance.

At this, Figure 16 to 18 shows the frequency characteristic of the loudspeaker unit of measuring 107 under the configuration of the simulation MFB shown in Figure 15.In addition, the low band resonant frequency f0 that supposes loudspeaker unit 107 in this case is 80Hz.

Figure 16 shows at MFB and is closed so that the frequency characteristic under the not operated situation.In other words, be directly inputted to power amplifier 103 and be exaggerated,, obtain this characteristic so that do not utilize low-band correction equalizer 101 to carry out to proofread and correct and do not utilize synthesizer 102 to apply under the situation that negative feedback drives loudspeaker unit 104 in audio signal.

Next, Figure 17 shows the characteristic of loudspeaker unit 107 under the situation of use (opening) MFB.Yet shown characteristic is the characteristic under the state that does not compensate by 101 pairs of low-frequency bands of low-band correction equalizer.

By Figure 16 and 17 is compared mutually, obviously, the power of close low band resonance frequency f 0 is compared when MFB is closed and is suppressed when opening MFB.This just shows that the vibration by using MFB low band resonance frequency f 0 place has effectively been suppressed.

Yet the said frequencies characteristic shown in Figure 17 can be understood that, for example under the situation of expectation flat frequency characteristic, and the state that the power of low-frequency band has been attenuated.Therefore, in MFB configuration shown in Figure 15, low-band correction equalizer 101 is disposed in the previous stage of synthesizer 102.In other words, the low-frequency band of the audio signal of the input that is decayed by MFB is proofreaied and correct (band compensation) in advance by low-band correction equalizer 101.

Figure 18 shows the frequency characteristic that is opened and is obtained at MFB under the situation by low-band correction equalizer 101 execution band compensations under the configuration shown in Figure 15.

In frequency characteristic shown in Figure 180, the power of low-frequency band one side has been compared the increase shown in Figure 17.Therefore, can obtain characteristic substantially than more smooth (smoothly) shown in Figure 17.In other words, by the band compensation of carrying out by low-band correction equalizer 101 frequency characteristic is strengthened.

For example, the equalization characteristic (correcting feature) of low-band correction equalizer 101 shown in Figure 15 is provided with as follows:

At first, measure the frequency characteristic of loudspeaker unit 107 under the state that MFB is opened after the audio signal of importing is by low-band correction equalizer 101.Then, calculate and allow measured frequency characteristic to become target frequency characteristic, for example smooth frequency characteristic, correcting value.In other words, obtain the gain that reformed frequency band and this frequency band may be needed.Then, for example the equalization characteristic of low-band correction equalizer 101 is set manually so that obtain above-mentioned correcting value.

In addition, under analog configuration, for example manually carry out setting for the yield value of amount of gain adjustment unit 108.

2. digital MFB: basic configuration

The above-mentioned configuration of MFB signal processing system shown in Figure 15 is disposed by analog circuit.On the other hand, in the present embodiment, by digital circuit configuration MFB signal processing system.

At first, Fig. 1 shows an example of the basic configuration that can be considered to digital MFB signal processing system.In addition, configuration shown in this Fig has under the situation of multichannel configuration corresponding to the audio frequency sound source as the source of audio signal, forms a passage in multichannel a plurality of passage.

As shown in Figure 1, at first, by simulated audio signal (audio signal of input) is input to ADC (A/D converter) 11, simulated audio signal is converted into digital audio and video signals and is imported into digital signal processing unit 10.

Digital signal processing unit 10 under this situation is for example formed by low-band correction equalizer 12, synthesizer 13, LPF20 and 21 configurations of gain controlling part.For example, digital signal processing unit 10 can be prepared by DSP (digital signal processor).Therefore, the signal processing of each can be realized by the program such as the instruction of being carried out by DSP etc. in the low-band correction equalizer 12 of digital signal processing unit 10, synthesizer 13, LPF20 and the gain controlling part 21.

The digital audio and video signals that is input to digital signal processing unit 10 is output to synthesizer 13 by low-band correction equalizer 12.Synthesizer 13 counter-rotatings are from feedback signal and the feedback signal that will reverse and the audio signal combination of exporting from low-band correction equalizer 12 of 21 outputs of gain controlling part.Therefore, can apply the negative feedback consistent to audio signal with the detection of the back electromotive force that in voice loop, generates.

Be imported into of the output of DAC (D/A converter) 14 from the digital audio and video signals of synthesizer 13 outputs as digital signal processing unit 10.

DAC14 is converted to the digital audio and video signals of input the form of analog signal and this simulated audio signal is outputed to power amplifier 15.

The simulated audio signal that power amplifier 15 will amplify after this simulated audio signal also will amplify offers loudspeaker unit (loud speaker) 16 as loudspeaker drive signal.Reproduce and the consistent sound of importing of audio signal according to the driven loudspeaker unit 16 of loudspeaker drive signal.

The known method that the motion of the vibrating membrane of loudspeaker unit 16 among several detection MFB is arranged.Use a kind of bridge detection method at this.According to the bridge detection method, bridgt circuit 17 as shown in the figure is provided with at the line that is arranged in the loudspeaker drive signal between power amplifier 15 and the loudspeaker unit 16.As shown in the figure, this bridgt circuit 17 for example comprises resistor R 1, R2 and R3, and forms by carrying out bridging for resistor as shown in the figure.

Detector/amplifier circuit 18 by bridge detection circuit 17 resistor R 1 and the electromotive force between the tie point of the tie point of R2 and loudspeaker unit 16 and resistor R 3, detect the back electromotive force that generates in the voice loop of the loudspeaker unit 16 that loudspeaker drive signal flows through.In the size of this detected back electromotive force corresponding to vibration, i.e. the motion of the vibrating membrane of loudspeaker unit 16.Especially, the size of detected back electromotive force is corresponding to the motion of the vibrating membrane of close low band resonant frequency f0.

Detection signal after detector/amplifier circuit 18 amplification detection signals under this situation will amplify then outputs to ADC (A/D converter) 19.

ADC19 is converted to the analog detection signal of self-detector/amplifier circuit 18 outputs digital signal and exports this digital signal to digital signal processing unit 10.

Be transfused to LPF (low pass filter) 20 from the digital detection signal of ADC19 output to digital signal processing unit 10.LPF20 for example is made of FIR filter etc.LPF20 allows to pass through corresponding to the band signal component of the frequency that is equal to or less than preset frequency, controls unwanted high fdrequency component thereby eliminate for MFB.Signal by LPF20 is imported into gain controlling part 21.

For example gain controlling part 21 for example is provided with the gain (feedback oscillator) corresponding to the input signal of feedback quantity, and consequential signal is outputed to synthesizer 13 as feedback signal.

By detecting the movement velocity that the signal that obtains has directly been represented vibrating membrane according to the bridge detection method by bridgt circuit 17.Then, the detection according to speed generates the feedback signal of obtaining by the frequency band through LPF20 restriction detection signal.In other words, MFB method (feedback method: shown in Figure 1 feedback) corresponding to the speed feedback type.

The phase place of synthesizer 13 counter-rotating feedback signals and with feedback signal and audio signal combination from 12 outputs of low-band correction equalizer.Therefore, can obtain the negative feedback operation as the speed feedback type.

The output of the synthesizer 13 under this situation is imported into DAC (D/A converter) 14 as the output audio signal of digital signal processing unit 10 and be converted into simulated audio signal.

Power amplifier 15 amplifies from the simulated audio signal of DAC14 output and the audio signal after will amplifying offers the voice loop of loudspeaker unit 16 as loudspeaker drive signal.

By loudspeaker drive signal is provided as mentioned above, reproduce by loudspeaker unit 16 corresponding to the sound of the audio signal of input.By the audio signal based on loudspeaker drive signal is applied speed feedback, be suppressed corresponding to for example motion near the vibrating membrane of the loudspeaker unit 16 of the frequency of low band resonance frequency f 0.In other words, can use MFB.Therefore, for example, the sound that loudspeaker unit 16 reproduces is strengthened.

In addition, as mentioned above, wherein the frequency characteristic that trends towards reducing near the power of low band resonance frequency f 0 is obtained by only using MFB.Correction or compensation that low-band correction equalizer 12 by digital signal processing unit 10 is carried out frequency characteristic.In other words, be used for proofreading and correct at the equalization characteristic (correcting feature) that ought only use the frequency characteristic that MFB obtains when becoming target frequency characteristic (for example, smooth characteristic) and be given low-band correction equalizer 12.Therefore, the audio signal by low-band correction equalizer 12 is by equilibrium, makes owing to use the power of the frequency band that MFB decayed and improved in advance.As a result, no matter whether used MFB, can obtain sound by loudspeaker unit 16 reproductions with desired frequency characteristic.

3. digital MFB: embodiment

3-1. profile instance

As shown in Figure 1, by utilizing digital circuit configuration MFB signal processing system, can not change physical assemblies constant, replace physical assemblies etc. and characteristic or operator scheme changed or switch between them.This can be by for example describing under the situation of digital information processing system by the DSP configuration, and what be provided with in will being given the program of DSP etc. wants reformed call parameter and constant, and realizes in simple mode.For example, under the situation of MFB signal processing system as shown in figure 15, be difficult to the setting that comes suitably to change automatically this type of parameter and constant according to the switching between characteristic or the operator scheme by the analog circuit configuration.

The initial purpose of MFB is so that keep fidelity and the sound quality that the fidelity of input audio signal strengthens audio reproduction as much as possible by the vibration vibration of membrane of control loudspeaker unit or motion.

With regard to present embodiment, a kind of configuration has been proposed, in this configuration, except realizing enhancing, by using above-mentioned advantage that digital circuit configuration MFB can obtain by more effective utilization as the fidelity of the initial purpose of MFB and sound quality.

Fig. 2 shows the profile instance according to the MFB signal processing system of present embodiment.MFB signal processing system as the embodiment shown in this figure also comprises the configuration of wherein using digital circuit.Therefore, give identical Reference numeral for each part identical, and the descriptions thereof are omitted with part shown in Fig. 1.

In digital signal processing unit shown in Figure 2 10, add difference processing part 22, LPF23 and gain controlling part 24 to the configuration shown in Fig. 1.For difference processing part 22, the audio signal that is input to the digital form of LPF20 from ADC19 is branched so that as input.

The audio signal of 22 pairs of inputs of difference processing part is carried out the Difference Calculation processing and consequential signal is exported to LPF23.As mentioned above, the signal that is obtained by the detection back electromotive force by bridgt circuit 17 can be considered the signal of the movement velocity of indication vibrating membrane.The difference that difference processing part 22 is calculated corresponding to the detection signal of above-mentioned speed.In other words, the signal that is obtained by difference processing part 22 (difference value) is corresponding to the acceleration of the motion of calculating vibrating membrane and be detection signal corresponding to this acceleration.LPF23 has removed for controlling unwanted high band component from the Accelerator Feedback of the differential signal of importing, that is, and and the detection signal of acceleration, and output result signal is given gain controlling part 24.24 pairs of input signals of gain controlling part apply necessary feedback oscillator and output result signal to the feedback signal of synthesizer 13 conducts corresponding to the Accelerator Feedback type.

Synthesizer 13 under this situation can make and combine with the feedback signal of exporting from gain controlling part 21 corresponding to the speed feedback type from the audio signal of low-band correction equalizer 12 outputs, and combine with the feedback signal of exporting from gain controlling part 24 by the application negative feedback corresponding to acceleration type.In other words, in configuration shown in Figure 2, the control of having made up speed feedback type and Accelerator Feedback type is configured to carry out as MFB.

It is to constitute by comprise the signal processing system that is arranged in LPF20 and gain controlling part 21 1 sides in closed-loop system that the MFB signal processing system of speed feedback type can be regarded as, and this closed-loop system is to constitute to feedback signal being fed back to synthesizer 13 from the audio signal output from synthesizer 13.

On the other hand, also can to regard as be to constitute by comprise the signal processing system that is arranged in difference processing part 22, LPF23 and gain controlling part 24 1 sides in above-mentioned closed-loop system to the MFB signal processing system of Accelerator Feedback type.

In configuration shown in Figure 2, as mentioned above, digital signal processing unit 10 as digital information processing system comprises corresponding to the LPF20 of speed feedback type and the system of gain controlling part 21, and corresponding to the system of difference processing part 22, LPF23 and the gain controlling part 24 of Accelerator Feedback type.This just shows can be in the operator scheme that only depends on the speed feedback type, only depend on the operator scheme of Accelerator Feedback type and speed feedback type and Accelerator Feedback type all effectively carries out between the operator scheme and switches, for example as one type switching between these operator schemes.As mentioned above, can realize this switching between the operator scheme in simple mode for digital circuit.

Especially, under the situation of carrying out the operation that only depends on the speed feedback type, carry out signal processing, and need not to carry out signal processing corresponding to difference processing part 22, LPF23 and gain controlling part 24 corresponding to LPF20 and gain controlling part 21.In addition, in this case, synthesizer 13 may reverse from the phase place of the feedback signal of gain controlling part 21 outputs and will only make up with the feedback signal that phase place is inverted from the audio signal of low-band correction equalizer 12 outputs.

On the other hand, under the situation of carrying out the operation that only depends on the Accelerator Feedback type, carry out signal processing, do not carry out signal processing corresponding to LPF20 and gain controlling part 21 corresponding to difference processing part 22, LPF23 and gain controlling part 24.In this case, synthesizer 13 counter-rotatings also will only be made up with the feedback signal that phase place is inverted from the audio signal of low-band correction equalizer 12 outputs from the phase place of the feedback signal of gain controlling part 24 outputs.

In addition, under the situation that speed feedback type and Accelerator Feedback type are all moved, all carry out corresponding to the signal processing of LPF20 and gain controlling part 21 and corresponding to the signal processing of difference processing part 22, LPF23 and gain controlling part 24.In this case, synthesizer 13 counter-rotating is from gain controlling part 21 and from the phase place of two feedback signals of gain controlling part 24 outputs, and will make up with the feedback signal that this two phase places be inverted from the audio signal of low-band correction equalizer 12 outputs.

At this, as the switching of above-mentioned MFB operator scheme, at first MFB is configured to open or close.In addition, under the situation of the pent operator scheme of MFB in Fig. 2 (MFB-closes pattern), the audio signal of input can be converted to digital form by ADC11, be input to digital signal processing unit 10, and export to DAC14 and need not to carry out the Digital Signal Processing relevant (can suitably carry out other necessary Digital Signal Processing) with MFB.

In addition, under the situation that MFB is opened, suppose the switching between the operator scheme (the 2nd MFB-on-mode) that operator scheme (a MFB-on-mode) that the speed feedback type only carried out is moved and speed feedback type and the anti-type of acceleration all moved.Yet, in the description here, for convenience of description for the purpose of, suppose that in

gain controlling part

21 and 24 each yield value that is provided with is set to be chosen to be a value of optimal value.

Active loudspeaker or similar device are as having a representational actual device that disposes shown in Fig. 2.

3-2. the correcting feature of equalizer is set

Under configuration shown in Figure 2, low-band correction equalizer 12 is by the digital circuit configuration such as FIR (finite impulse response) filter or IIR (infinite impulse response) filter.Therefore, can be easy to change the setting of correcting feature.Thus, under the prerequisite of the switching of carrying out above-mentioned MFB operator scheme, the example of the setting of the correcting feature of description low-band correction equalizer 12.

At first, Fig. 3 is illustrated under the situation of any one pent MFB-pass pattern among MFB signal processing system medium velocity feedback-type MFB shown in Fig. 2 and the Accelerator Feedback type MFB, the frequency characteristic of loudspeaker unit 16.

In addition, Fig. 4 is illustrated in that the MFB signal processing system medium velocity feedback-type MFB shown in Fig. 2 is opened and under the situation of the pent MFB-on-mode of Accelerator Feedback type MFB, the frequency characteristic of loudspeaker unit 16.Yet the audio signal by 12 pairs of inputs of low-band correction equalizer does not apply the frequency band correction.

Fig. 5 is illustrated under the situation of the 2nd MFB-on-mode that the MFB signal processing system medium velocity feedback-type MFB shown in Fig. 2 and Accelerator Feedback type MFB all be opened, the frequency characteristic of loudspeaker unit 16.Under situation shown in Figure 5, be similar to situation shown in Figure 4, the audio signal by 12 pairs of inputs of low-band correction equalizer does not apply the frequency band correction.

No matter can observe from these figure, be in a MFB-on-mode shown in Figure 4 or in the 2nd MFB-on-mode shown in Figure 5, compares MFB-shown in Figure 3 and close pattern, and near the power the low band resonance frequency f 0 reduces.In other words, no matter be in a MFB-on-mode or in the 2nd MFB-on-mode, the vibrating membrane of loudspeaker unit it seems that the FEEDBACK CONTROL that is used as MFB effectively blocks, and this just becomes the basis of the enhancing of reproducing sound.

Yet the characteristic of characteristic by a MFB-on-mode more shown in Figure 4 and the 2nd MFB-on-mode shown in Figure 5 can be observed, although the first and second MFB-on-mode all are one of MFB-on-mode, their characteristic is different.For example, in the 2nd MFB-on-mode shown in Figure 5 near power the low band resonance frequency f 0 than being tending towards stronger in the MFB-on-mode shown in Figure 4.The difference for the condition of FEEDBACK CONTROL is depended in a MFB-on-mode and the 2nd MFB-on-mode in this difference.

Then, characteristic as the low-band correction equalizer 12 under this situation, according to determining two correcting features of equalizer to make these two characteristics become target frequency characteristic corresponding to the characteristic shown in Figure 4 of a MFB-on-mode and corresponding to the characteristic shown in Figure 5 of the 2nd MFB-on-mode.

At this, target frequency characteristic is assumed that it is smooth (level and smooth) characteristic.In other words, no matter be in a MFB-on-mode or in the operator scheme of the 2nd MFB-on-mode, dispose smooth characteristic finally to be obtained the frequency characteristic of the sound that reproduces as loudspeaker unit 16.

In the case, the frequency characteristic of a MFB-on-mode and the 2nd MFB-on-mode is different shown in Figure 4 and 5.Therefore, in order should to be that a MFB-on-mode is provided with different correcting features with the 2nd MFB-on-mode in the flat frequency characteristic of under the 2nd MFB-on-mode, obtaining loudspeaker unit 16 under the MFB-on-mode again.In other words, corresponding to a MFB-on-mode, obtaining its characteristic flattens smooth with the frequency characteristic that allows measurement as shown in Figure 4 reformed target frequency, and obtain the parameter that will reformed target frequency be applied for characteristic (as, gain), and correcting feature is determined according to described parameter.Similarly, corresponding to the 2nd MFB-on-mode, obtaining its characteristic flattens smooth with the frequency characteristic that allows measurement as shown in Figure 5 reformed target frequency, and obtain the parameter that will reformed target frequency be applied for characteristic (as, gain), and correcting feature is determined according to described parameter.

Then, in the operation of the MFB of reality signal processing system, at first, when a MFB-on-mode was set to operator scheme, the feasible correcting feature corresponding to a MFB-on-mode of parameter that low-band correction equalizer 12 is set was set up.Similarly, when the 2nd MFB-on-mode was set, the feasible correcting feature corresponding to the 2nd MFB-on-mode of parameter that low-band correction equalizer 12 is set was set up.

Therefore, even when being provided with any one of a MFB-on-mode and the 2nd MFB-on-mode, for example as shown in Figure 6, can obtain the flat characteristic that its rising is obtained by the power of proofreading and correct low-frequency band, as the frequency characteristic of loudspeaker unit 16.

On the other hand, when operator scheme is MFB-pass pattern, input audio signal is set so that by low-band correction equalizer 12.

3-3. application example (first example)

Yet, even when the frequency characteristic of a MFB-on-mode and the 2nd MFB-on-mode all is corrected as above-mentioned smooth frequency characteristic, the sound pattern of the reality that loudspeaker unit 16 reproduces is also all obviously different in a MFB-on-mode and the 2nd MFB-on-mode.The inventor has checked this phenomenon practically.

For instance, such result is because the different FEEDBACK CONTROL conditions of a MFB-on-mode and the 2nd MFB-on-mode cause.Therefore, the same although the frequency characteristic of measuring is corrected as, difference to some extent between the retardance state of the vibrating membrane of actual loudspeaker unit 16 in a MFB-on-mode and the 2nd MFB-on-mode.

For example, Fig. 7 A to 7C shows the difference under the situation that difference in the retardance state of vibrating membrane of loudspeaker unit 16 is considered transient phenomenon.Fig. 7 A to 7C is a schematic diagram, only is used for the difference of easy to understand for the transient phenomenon of every kind of operator scheme.

Fig. 7 A shows the characteristic of closing the pattern situation corresponding to the MFB-of Fig. 3, and Fig. 7 B shows the characteristic corresponding to the MFB-on-mode situation of Fig. 4, and Fig. 7 C shows the characteristic corresponding to the 2nd MFB-on-mode situation of Fig. 5.These figure can regard as, are right after constantly 0 and stop near the measurement of the motion of vibrating membrane (the low band resonance frequency f 0) is provided after the drive signal to loudspeaker unit 16.

Close at MFB-under the situation of pattern, the damping that produces because of MFB is invalid.Therefore, shown in Fig. 7 A, after 0 past constantly, form the slowly characteristic of decay of amplitude.

On the other hand, in the MFB-on-mode shown in Fig. 7 B, apply decay based on the MFB of speed feedback type.Therefore, amplitude is decayed comparing in the shorter time shown in Fig. 7 A from 0 beginning constantly.This expression for example vibration mode of the sound of so-called " buzz " is suppressed so that be enhanced.

In addition, in the 2nd MFB-on-mode shown in Fig. 7 C, amplitude was decayed in the short time of 0 beginning constantly.Yet, compare the situation of Fig. 7 B, formed the wherein elongated a little image of time of amplitude fading of a width of cloth.As a kind of explanation, this expression " buzz " is subjected to and the same inhibition of situation shown in Fig. 7 B, and compares with the situation shown in Fig. 7 B and to form one the residual listen mode of a little reverberation is arranged.

Although as mentioned above frequency characteristic be corrected as in a MFB-on-mode and the 2nd MFB-on-mode identical, still variant between the sense of hearing impression of the sound that in loudspeaker unit 16, reproduces and the listen mode.

Difference between the listen mode of the one MFB-on-mode and the 2nd MFB-on-mode does not represent that a kind of pattern just definitely is better than another kind of pattern.Thus, this difference can be thought to show according to any pattern of audience's taste and all caters to the need.In addition, for identical audience, can as style, change and think desirable pattern according to the type of sound source that will be reproduced.

In this viewpoint, under the situation of MFB signal processing system, can consider to be used for the application of switching between a MFB-on-mode and the 2nd MFB-on-mode that operates in according to the user by digital circuit configuration.

In other words, except the change of the open/close state of MFB, can carrying out any selection according to the taste of the sound consistent with opening MFB, will to switch to a MFB-on-mode still be the operation of the 2nd MFB-on-mode.

According to the handover operation between the operator scheme of MFB, for example by the data of the mode setting table shown in digital signal processing unit 10 storage maps 8.

In mode setting table shown in Figure 8, at first, definition MFB-closes the operator scheme item in pattern, a MFB-on-mode and the 2nd MFB-on-mode.Can select any one the operation in these operator schemes as MFB.Then, the content of ON/OFF setting of content, Accelerator Feedback type MFB of the ON/OFF setting of speed feedback type MFB and the equalizer correcting feature that will be provided with in low-band correction equalizer 12 are associated with each operator scheme.

Among Fig. 8, close pattern corresponding to MFB-, expression speed feedback type MFB will be closed with Accelerator Feedback type MFB and will be closed.In addition, about the equalizer correcting feature, low-band correction equalizer 12 is represented as and will be passed through.

On the other hand, corresponding to a MFB-on-mode, expression speed feedback type MFB will be opened and Accelerator Feedback type MFB will be closed.In addition, write " characteristic 1 " in the drawings as the equalizer correcting feature.Yet in fact, characteristic is reformed target frequency, and characteristic is designated as the parameter (as gain) at reformed target frequency place and for example is used to correcting feature (equalization characteristic) that frequency characteristic is flattened.

On the other hand, represent that speed feedback type MFB will be opened and Accelerator Feedback type MFB will be opened.About writing the equalizer correcting feature of " characteristic 2 ", specified the parameter that is used to make the correcting feature that the frequency characteristic corresponding to the 2nd MFB-on-mode flattens.

At this, suppose according to user's operation and selected MFB-to close pattern.Therefore, for example as the digital signal processing unit 10 of DSP close with reference to mode setting table identification shown in Figure 8 and MFB-pattern association speed feedback type MFB open/close content, Accelerator Feedback type MFB be set open/close content and equalizer correcting feature be set.Then, the signalization treatment system makes that speed feedback type MFB is closed, Accelerator Feedback type MFB is closed, low-band correction equalizer 12 will be passed through.As a result, constituted the digital information processing system of MFB-pass pattern.

On the other hand, corresponding to the selection of a MFB-on-mode, digital signal processing unit 10 forms signal processing system according to be provided with open/close content and the equalizer correcting feature that open/close content, Accelerator Feedback type MFB are set of speed feedback type MFB related with a MFB-on-mode in the mode setting table.In other words, in digital signal processing unit 10, form a closed loop, make that speed feedback type MFB is opened, Accelerator Feedback type MFB is closed, and in low-band correction equalizer 12, the parameter by " characteristic 1 " expression is set.

On the other hand, corresponding to the selection of the 2nd MFB-on-mode, digital signal processing unit 10 forms signal processing system according to be provided with open/close content and the equalizer correcting feature that open/close content, Accelerator Feedback type MFB are set of speed feedback type MFB related with the 2nd MFB-on-mode in the mode setting table.In other words, in digital signal processing unit 10, form a closed loop, make speed feedback type MFB and Accelerator Feedback type MFB all be opened, and in low-band correction equalizer 12, the parameter by " characteristic 2 " expression is set.

3-4. application example (second example)

In application, be assumed to the yield value (feedback oscillator value) that a MFB-on-mode and the 2nd MFB-on-mode be provided with and be fixed to unique in

gain controlling part

21 and 24 corresponding to first example of mode setting table shown in Figure 8.

Yet the parameter of gain controlling part 21 that comprises in the digital signal processing unit 10 as digital circuit and 24 yield value can change in an easy manner and be provided with.For example, each gain of

gain controlling part

21 and 24 is set by the operator scheme that all is opened for speed feedback type MFB and Accelerator Feedback type MFB, can suitably changes the feedback quantity of speed feedback type MFB and the feedback quantity of Accelerator Feedback type MFB and be used for being provided with.Therefore, along with each feedback quantity of speed feedback type MFB or Accelerator Feedback type MFB is changed, the listen mode of the sound that reproduces in the loudspeaker unit 16 changes according to the combination of the feedback quantity of speed feedback type MFB and Accelerator Feedback type MFB.In addition, for example, compare with the situation of the open/close combination of Accelerator Feedback type MFB with the ON/OFF of operating speed feedback-type MFB, the listen mode of sound can be set more subtly according to the combination of the feedback quantity of speed feedback type MFB and Accelerator Feedback type MFB, and this is identical with the application in first example.

For example, even under the situation of using identical audio-source, suitable acoustic tones is for also being different such as the sound of the video content of film with sound such as the audio content of CD.For example, for create atmosphere, reverberation is to a certain degree arranged in the sound of film etc.On the other hand, because the sound of audio content needs more Hi-Fi reproduction, the preferably reverberation of the acoustic phase same level of reservation and film.In addition, think that the acoustic tones of desired audio content is different, for example according to style of music or the like.

Consider said circumstances, following configuration the application's second example.

At first, pre-determine the combination of the feedback quantity of speed feedback type MFB and Accelerator Feedback type MFB, the i.e. yield value that in

gain controlling part

21 and 24, is provided with, at its obtain be suitable for reproducing such as the acoustic tones of the content type of the audio-source of film or music or be suitable for the acoustic tones of the style of audio content.

Then,, for example generate gain-correcting feature table as shown in Figure 9 according to determined content, and in digital signal processing unit 10 storage gain-correcting feature table.

As shown in Figure 9, at first, each list item is classified as the content type of film and music basically.In addition, the content type of music is again according to the genre classification as rock and roll, jazz and allusion.In addition, film, rock and roll, jazz and classic each are associated with the gain of speed feedback type MFB, gain and the equalizer correcting feature of Accelerator Feedback type MFB.

As the gain of speed feedback type MFB, be illustrated in the yield value corresponding to speed feedback type MFB that will be provided with in the gain controlling part 21.At this, the yield value corresponding to film, rock and roll, jazz and classic each that will be provided with in gain controlling part 21 is represented by a1, b1, c1 and d1.

Similarly, as the gain of Accelerator Feedback type MFB, be illustrated in the yield value corresponding to Accelerator Feedback type MFB that will be provided with in the gain controlling part 24.At this, the yield value corresponding to film, rock and roll, jazz and classic each that will be provided with in gain controlling part 24 is represented by a2, b2, c2 and d2.

Therefore, when the combination of the feedback quantity of the feedback quantity of speed feedback type MFB and Accelerator Feedback type MFB, i.e. yield value (feedback oscillator value) when being changed, the frequency characteristic of the sound that reproduces from loudspeaker unit 16 that obtains based on this combination changes.Therefore, for by utilizing low-band correction equalizer 12 correcting frequency characteristics to make it smooth, for example as mentioned above, may need the equalizer correcting feature to be set according to the frequency characteristic of obtaining based on the combination of yield value.The equalizer correcting feature of arranging in gain shown in Figure 9-correcting feature table has been represented the equalization characteristic of basis corresponding to the low-band correction equalizer 12 of the frequency characteristic setting of each combination of every yield value.

The user is allowed to carry out the selection operation of content type and style.When corresponding to the content of table data shown in Figure 9, can from " film " and " rock and roll " of the content type of music, " jazz " and " allusion " four options, select one as this operation.

Then, the content type of making according to user's operation and the selection of style, digital signal processing unit 10 obtains the gain of the speed feedback type MFB related with selected content type or style, gain and the equalizer correcting feature of Accelerator Feedback type MFB from gain-correcting feature table.Then, digital signal processing unit 10 changes the yield value of

gain controlling parts

21 and 24 and the equalization characteristic of the low-band correction equalizer 12 that will be provided with according to the content of being obtained.

As mentioned above, in the application of second example, the selection of the content type of the reproduced audio-source that will be used to specify and style is provided with automatically the effective status of the MFB that is suitable for selected content type and style according to the user.In other words, change the effective status of MFB, with the acoustic tones of the reproduction sound that obtains the content type that is suitable for the specified audio-source of user and style.

Content type shown in Figure 9 and style only are examples.In addition, in the application of second example, described speed feedback type MFB and Accelerator Feedback type MFB all is opened, and the yield value (feedback quantity) of each content type and style is changed and is used for being provided with in the description of the application of second example.Yet, in second example, also be used in combination the open/close combination of speed feedback type MFB and Accelerator Feedback type MFB.For example, the setting that can use speed feedback type MFB only to be opened, and the yield value under this situation is changed.

In addition, in the application of the first above-mentioned example, for example it is also conceivable that for example MFB-is closed the user interface of the selection operation use of pattern, a MFB-on-mode and the 2nd MFB-on-mode according to second example.In other words, for example, for MFB-closes the expression formula that each option of pattern, a MFB-on-mode and the 2nd MFB-on-mode is given representative voice tone or style title, content type etc.

In addition, in description up to now, the equalizer correcting feature of supposing low-band correction equalizer 12 is that flat characteristic is as target frequency characteristic.Yet this only is an example.As long as can acoustically obtain a good result, can be provided with such as low-frequency band and be thus lifted to specific rank or any characteristic of the characteristic that is cut, as the target frequency characteristic except that flat characteristic.

In addition, may to need not be to the operator scheme of MFB or general to the combination of feedback quantity to target frequency characteristic.For example, in order to obtain more desirable acoustic tones, can be wittingly different frequency characteristics be set for the combination of the operator scheme of MFB or feedback quantity.

4. digital MFB: revise example

Up to now, described according to wherein using the bridge detection method basically and being used in combination speed feedback type MFB and the configuration of the embodiment of Accelerator Feedback type MFB.

According to this bridge detection method, detect back electromotive force by bridgt circuit 17.Therefore, recognized the advantage of bridge detection method: for example in the vibrating membrane of loudspeaker unit 16 grades, do not need to arrange physical sensors, with and physical structure uncomplicated.

Yet, as the detection method that is used for MFB, known except that the bridge detection method for example by utilizing the direct capacitance device, laser displacement systems etc. detect the method for displacement of the vibrating membrane of loudspeaker unit 16.

Therefore, as the correction example of the MFB signal processing system of present embodiment, figure 10 illustrates the profile instance that adds displacement detecting to configuration shown in Figure 2.In Figure 10, give identical Reference numeral to the part identical, and its description is omitted with the part of Fig. 2.

As shown in figure 10, at first, arrange the displacement transducer 29 of the displacement of the vibrating membrane be used to detect loudspeaker unit 16.Displacement transducer 29, for example by the direct capacitance device, configurations such as laser displacement system.The analog detection signal that obtains by the displacement of the vibrating membrane in the detecting position displacement sensor 29 is exaggerated 25 amplifications of device circuit and is converted to digital signal by ADC26, so that output to digital signal processing unit 10.

Digital signal processing unit 10 in this situation also comprises LPF27 and gain controlling part 28.By allowing to pass through LPF27, eliminated unnecessary high band component, and applied gain by gain controlling part 28 from the digital displacement detection signal of ADC input.Then to synthesizer 13 output result signals as feedback signal.

Synthesizer 13 in this situation can reverse from the feedback signal corresponding to the speed feedback type of gain controlling part 21 outputs, feedback signal from 24 outputs of gain controlling part corresponding to the Accelerator Feedback type, with from gain controlling part 28 output corresponding to the displacement detecting method feedback signal of (can be considered to Displacement Feedback method) as feedback method, and will make up by the audio signal of low-band correction equalizer 12 and feedback signal through counter-rotating.

Under this configuration, in the application of first example, speed feedback type MFB, Accelerator Feedback type MFB, be changed with the open/close combination of the MFB that carries out based on the detection of displacement, and the correcting feature of low-band correction equalizer 12 also is changed according to this combination and is provided with.

In addition, application corresponding to second example, determine the combination of the yield value of

gain controlling part

21,24 and 28 according to predefined content type and style, and the equalizer correcting feature of determining based on yield value with according to each combination be combined to form gain-correcting feature table.

As mentioned above, with regard to present embodiment, the number of the MFB detection method that is used in combination and the integrated mode of detection method are not specially limited.

In addition, even when using identical detection method, also can suitably change the configuration that is used to detect, be used for configuration of signal processing or the like with identical feedback method.For instance, with regard to the speed corresponding to speed feedback type MFB detects, for example, also become known in loudspeaker unit 16, arranging the technology of magnetic test coil.In addition, the signal that can acquisition speed detects of the integration by sense acceleration and signal calculated.In addition, for acceleration detection, can use acceleration transducer, the acoustic pressure that perhaps can use by using microphone detects.

5. the adjustment of feedback oscillator

5-1. the adjustment in the analog circuit

The yield value of the feedback oscillator of MFB signal processing system is set, for example makes and to obtain the feedback quantity of expectation.Yet although identical yield value is set, the actual feedback quantity that obtains is because of the variation of the characteristic of loudspeaker unit, such as variation of the simulated assembly of the motion that is used to detect vibrating membrane etc. and different.Therefore, in order to absorb above-mentioned variation and in fact to obtain suitable feedback quantity, preference is adjusted feedback oscillator as transport product at least one stage before the user from factory.

Therefore, at first, figure 19 illustrates the profile instance that uses analog circuit, can adjust the MFB signal processing system of feedback oscillator.Configuration shown in Figure 19 has configuration shown in Figure 15 as its basis.Therefore, give identical Reference numeral for each part identical, and the descriptions thereof are omitted with part shown in Figure 15.

As shown in figure 19, between the input of the output of amount of gain adjustment unit 108 and synthesizer 102, insert switch SW 1.In addition, between the input of the output of low-band correction equalizer 101 and synthesizer 102, insert switch SW 2.Switch SW 1 is the conduction and cut-off switch, and switch SW 2 is to change terminal tm1 to any change over switch that is connected of terminal tm2 and tm3.The terminal tm1 of switch SW 2 is connected to the input of synthesizer 102, and the terminal tm2 of switch SW 2 is connected to the output of low-band correction equalizer 101.In addition, terminal tm3 opens corresponding to normal running.

In normal running, as shown in figure 19, switch SW 1 is opened, and terminal tm1 is connected to the terminal tm2 in the switch SW 2.Therefore,, form closed loop circuit shown in Figure 1, and the audio signal of input is output to synthesizer 102 by low-band correction equalizer 12 as the MFB signal processing system.In other words, formed the circuit of the normal signal processing that can carry out MFB.

On the other hand, in order to adjust feedback oscillator, as shown in figure 20, switch SW 1 is closed.Therefore, the output of amount of gain adjustment unit 108 is not input to synthesizer 102, thereby forms an open loop.Switch SW 2 is shifted with splicing ear tm1 to terminal tm3, and the measuring-signal that is used for the feedback oscillator adjustment is imported into terminal tm3.Therefore, measuring-signal but not the audio signal of audio-source is imported into the MFB signal processing system of open loop.

In addition, the measuring-signal as corresponding to the MFB signal processing system that is disposed by analog circuit for example, can use corresponding to frequency band to be measured the sine sweep signal of white noise etc.

In addition, the output of amount of gain adjustment unit 108 is imported into the measurement monitoring arrangement, for example as supervisory signal.

In configuration shown in Figure 20, the measuring-signal that is input to the terminal tm3 of switch SW 2 passes through power amplifier 103, loudspeaker unit 104, bridgt circuit 105, detector/amplifier circuit 106, low pass filter 107 and amount of gain adjustment unit 108 are acquired as supervisory signal.

The frequency characteristic of supposing supervisory signal is as shown in figure 21 as the result who measures.Therefore, supervisory signal has characteristic: obtain peak value at low band resonant frequency f0=80Hz place.For instance, here, MFB signal processing system hypothesis applies the feedback of 12dB at the closed loop state.When the feedback quantity (magnification ratio) of closed loop when being represented by α, open-loop gain is α-1.

Therefore, in the case, for example, adjust the variable resistor device of operating personnel's manual adjustment as amount of gain adjustment unit 108, observe supervisory signal simultaneously, make that peak power at low band resonant frequency f0=80Hz place is 3 times of power (level) of measuring-signal.

As mentioned above, for the situation of the MFB signal processing system that is disposed by analog circuit, feedback oscillator may need to pass through manual adjustment.Therefore, be difficult to carry out the accurate adjustment of feedback oscillator for each equipment with MFB signal processing system.

In addition, for the situation of analog circuit, for example, the stage before transporting has been adjusted after the feedback oscillator, and switch SW 1 and SW2 are displaced to state shown in Figure 19 from state shown in Figure 20, and for example, this device is assembled etc., is transported then.Therefore, usually in being passed to stage of domestic consumer, this device is difficult to adjust feedback oscillator.In other words, generally speaking, the adjustment of feedback oscillator is confined to the fabrication stage.Even when this equipment is configured to make that the variable resistor device of switch SW 1 and SW2 and amount of gain adjustment unit can be operated simply by domestic consumer, also may needs measuring equipment etc. to be used for adjusting, and may need corresponding techniques.In other words, preferably do not allow domestic consumer can adjust this device.

5-2. the adjustment in the digital circuit

Therefore, with regard to present embodiment, the following configuration that can adjust feedback oscillator is automatically proposed.

Figure 11 show by digital circuit configuration be used to adjust the profile instance of MFB signal processing system of feedback oscillator as an embodiment.In the figure, give identical Reference numeral for each part identical, and the descriptions thereof are omitted with the part shown in Fig. 1 and 2.With regard to present embodiment, shown in Fig. 2 waits, include a plurality of configurations in the Digital Signal Processing stage and be used as its basic configuration with feedback control system of different feedback methods.Yet in order to understand specification easily, Figure 11 shows the profile instance based on the configuration of the feedback control system that only includes a speed feedback type shown in Figure 1.

Under MFB signal processing system by the present embodiment of digital circuit configuration, when adjusting feedback oscillator, form digital signal processing unit 10 as shown in figure 11, for example, DSP, signal processing operations.In other words, digital signal processing unit 10 is configured to comprise measuring-signal generating portion 31, playback buffer device 32, and LPF20, buffer 33, FFT part 34, contrary-TSP processing/feature extraction part 35 and gain are provided with part 36.

Measuring-signal generating portion 31 in this situation is digital circuits and thus, for example, generates TSP (temporal extension pulse) signal as measuring-signal.In other words, impulse response is measured and is used for the measurement of adjusting feedback oscillator and carrying out here.The TSP signal that is generated by measuring-signal generating portion 31 is stored in the playback buffer device 32.At first, the data of reading from playback buffer device 32 are set up as digital TSP signal and by output from digital signal processing unit 10.This TSP signal is converted to analog signal by DAC14 and is amplified by power amplifier 15, so that be provided for the voice coil of loudspeaker unit 16.Be bridged circuit 17 according to the motion of the vibrating membrane of the loudspeaker unit 16 of this moment TSP signal and detect and be output to ADC19 as the amplification detection signal that comes self-detector/amplifier circuit 18.ADC19 is converted to the analog detection signal of input digital detection signal and exports this digital detection signal.

In digital signal processing unit 10,, eliminated unnecessary high band component by passing through LPF20 from the digital detection signal of ADC19 output.Buffer 33 loads the TSP response signal by many pre-determined numbers of LPF20, and for example, calculating mean value, and this mean value is sent to FFT part 34.

In FFT part 34, carry out the frequency analysis of for example using FFT (fast fourier transform) for the TSP response signal after average and handle.In addition, contrary-TSP processing/feature extraction part 35 is to carry out contrary-TSP from the data that TTF part 34 transmits to handle.Therefore, in this case, with regard to the MFB signal processing system of open loop, obtained the characteristic of the measuring-signal of system's transmission of passing through the speed feedback type.

Therefore, gain is provided with part 36 and based on the difference that appears at by between the value of the value of the peak level (low band resonant frequency f0) in the frequency characteristic of contrary-TSP processings/feature extraction part 35 measurements and target peak level feedback oscillator is set.For example, at the represented peak level of frequency characteristic by contrary-TSP processing/feature extraction part 35 measurements be-5dB, the target peak level is under the situation of 9dB, and feedback oscillator is 9-(5)=14dB.

MFB signal processing system shown in Figure 11 is open loop.Be difficult to carry out the measurement that is used to be provided with feedback oscillator, unless the MFB signal processing system is open loop.Therefore, the feedback oscillator that obtains up to this stage has the value corresponding to open loop.Under the situation that in fact MFB applies by the MFB signal processing system, form closed loop shown in Figure 1.Yet, have the feedback oscillator of target peak level, that is this moment, the feedback oscillator during closed loop, the feedback oscillator during with respect to open loop has error.

Feedback oscillator value when the feedback oscillator value when therefore, gain is provided with part 36 based on above-mentioned open loop of obtaining is obtained closed loop.The object lesson of calculation expression has omitted.Yet the calculating of the feedback oscillator value that the feedback oscillator value when closed loop can be when utilizing above-mentioned open loop of obtaining comes unique obtaining.

The feedback oscillator value that digital signal processing unit 10 storage is above-mentioned when by gain the closed loop that part 36 obtains being set is as the parameter that is provided with in gain controlling part 21.Then, when in fact allowing the MFB signal processing system, for example, under the situation corresponding to Figure 11, digital signal processing unit 10 forms signal processing system shown in Figure 1.At that time, the feedback oscillator value of storage is provided with in gain controlling part 21.

As mentioned above, in the feedback oscillator of present embodiment is adjusted, obtain optimal value automatically.In addition, when the measurement of carrying out for open loop, the yield value in the time of can finally obtaining corresponding to closed loop.

In addition, above-mentioned can self-adjusting feedback oscillator can redescribe into, even when the feedback oscillator value for example is configured to operation etc. according to the user and can adjusts, can not occur as the worry in the situation of analog circuit yet.

Therefore, the equipment with MFB signal processing system of present embodiment is configured to make, can carry out the operation of the adjustment that be used to instruct the feedback oscillator value according to user's operation.Then, according to the operation of the adjustment that is used to instruct the feedback oscillator value, digital signal processing unit 10 at first forms the signal processing system of open loop shown in Figure 11, begins to measure the feedback oscillator value when finally obtaining closed loop, and the feedback oscillator value obtained of storage.Then, when after when moving the MFB signal processing system, the feedback oscillator value of up-to-date storage is set up in the gain controlling part.

For example, along with change of time etc., the reproducing characteristic of loudspeaker unit 16 or the characteristic of simulated assembly may change.When the change of this specific character takes place, for example the yield value that is provided with up to now with along with in fact this change error occurs between the yield value of optimum.When feedback oscillator value as mentioned above can be according to the operating in random time and readjusted of user, can be set to optimum and operate MFB by change the feedback oscillator value along with the above-mentioned time usually.

In addition, in fact, shown in Fig. 2 and 10, in application combination under the situation of configuration of MFB signal processing system of a plurality of feedback control systems, the feedback oscillator value in the time of can obtaining the closed loop of each system.

For instance, under situation, form the MFB signal processing system by the open loop of further adding the Accelerator Feedback type to configuration shown in Figure 11 corresponding to the configuration of Fig. 2.In other words, at first, in digital signal processing unit 10, arrange difference processing part 22 and LPF23 shown in Figure 2.Even in this case, the digital detection signal from ADC19 output can be branched and be input to difference processing part 22.In addition, in the back one-level of LPF23, by buffer 33, FFT part 34, contrary-TSP processing/feature extraction part 35 and gain be provided with that part 36 forms corresponding to the parallel setting of system of the system of Accelerator Feedback type with speed feedback type shown in Figure 11.Therefore, be in gain controlling part 24 corresponding to the yield value of Accelerator Feedback type setting with will in gain controlling part 21, obtaining by the yield value corresponding to the setting of speed feedback type.

In addition, under the situation of yield value, use similar MFB control, obtain the feedback oscillator value according to each corresponding to table data shown in Figure 9 according to the configuration of each change of content type or style.In the case, for the signal processing system of the like combinations with the feedback method that will be opened, by the measured feedback oscillator value of obtaining corresponding to a signal processing system, this becomes the basis in them.Next, consider following method: for example, be that other signal processing systems are provided with the side-play amount with respect to basic feedback oscillator value, deviation ratio or the like, and obtain each feedback oscillator value by calculating.

6. the adjustment of the correcting feature of equalizer

6-1. the adjustment in the analog circuit

Under the above-mentioned situation that can adjust the feedback oscillator value,, need not change the frequency characteristic that equalization characteristic also can change the reproduction sound of loudspeaker unit 16 even when the feedback oscillator value is changed.Therefore, the correcting feature of low-band correction equalizer 12 (equalization characteristic) also needs to be provided with once more according to adjusted feedback oscillator value.

Therefore, for example, for the MFB signal processing system by the analog circuit configuration shown in Figure 1, equalization characteristic can followingly be provided with.

At first, arrange the microphone be used for being received in the sound that loudspeaker unit 16 reproduces, and be set to MFB signal processing system shown in Figure 1 under the state of flat characteristic according to close loop maneuver in the characteristic of low-band correction equalizer 101.In other words, MFB is opened.Then, under the state that MFB is opened, measure the frequency band of the audio signal of obtaining by the sound that receives from microphone.The operator for example, manually changes the equalization characteristic of low-band correction equalizer 101, monitors measured frequency characteristic simultaneously, makes that measured frequency characteristic is a target frequency characteristic.

As mentioned above, under the state that MFB is opened, in the MFB signal processing system by the analog circuit configuration, the adjustment of equalization characteristic may need manual execution, needs measurement mechanism thus.Therefore, under the situation of considering common situation, execution previous stage that is adjusted at the fabrication stage or transports of equalization characteristic from factory, and be not suitable for allowing the user to adjust equalization characteristic.

6-2. the adjustment in the digital circuit

Figure 12 shows the profile instance of the adjustment of the equalization characteristic (equalizer correcting feature) corresponding to present embodiment.Even in this case, be convenient and describe, show use only by the configuration under the prerequisite of the MFB signal processing system of the system configuration of a speed feedback type.In Figure 12, give identical Reference numeral for each part identical, and the descriptions thereof are omitted with part shown in Figure 11.Configuration shown in Figure 12 is that the equalizer correcting feature is provided with part 37 and parameter storage area 38 forms by adding to configuration shown in Figure 11.Feedback oscillator value β during closed loop that parameter storage area 38 storage in this situation will be provided with in gain controlling part 21 and with low-band correction equalizer 12 therein in the equalizer correcting feature γ of setting, as parameter.

The equalizer correcting feature is provided with part 37 based on the feedback oscillator value β new that part 36 newly obtains being set by gain and being stored in feedback oscillator value β and equalizer correcting feature γ in the parameter storage area 38, obtains the new equalizer correcting feature γ new corresponding to the feedback oscillator value β new that newly obtains.

Figure 13 represents to be provided with the process of the equalizer correcting feature of being carried out by digital signal processing unit shown in Figure 12 10, as flow chart.In addition, the step of representing among this figure for example, can be considered to by gain part 36 or equalizer correcting feature to be set and be provided with that part 37 suitably carries out.

At first, gain is provided with the feedback oscillator value α of part 36 when step S101 measures corresponding to open loop, and the new feedback oscillator value β new when step S102 calculates in new closed loop by the calculating of using feedback oscillator value α.The process of step S101 and S102 can be carried out by top order with reference to Figure 11 description.

Next, at step S103, the equalizer correcting feature is provided with part 37 and reads feedback oscillator value β and the equalizer correcting feature γ that is stored in the parameter storage area 38.

Then, at step S104, the equalizer correcting feature is provided with part 37 based on using the feedback oscillator value β that reads at step S103 and equalizer correcting feature γ and in the calculating of the precalculated new feedback oscillator value β new of step S102, calculating new equalizer correcting feature γ new.

The description of the object lesson of the calculation expression of calculating equalizer correcting feature γ new is omitted.Yet, as a kind of computational algorithm, for example, at first, obtain new feedback oscillator value β new and the feedback oscillator value β that uses up to now between difference.Then, obtain the error of for example supposing the frequency characteristic that generates according to the difference of being obtained.When getting access to this error, unique correcting value that obtains the balancer characteristic that is used to compensate this error.Then, calculate to change the equalizer correcting feature γ that uses up to now, obtain new equalizer correcting feature γ new according to correcting value by carrying out.

Then, the equalizer correcting feature be provided with part 37 be provided with the above-mentioned equalizer correcting feature γ new that newly obtains as after to be stored in equalizer correcting feature γ in the parameter storage area 38 at step S105.Similarly, the equalizer correcting feature is provided with part 37 and is arranged on the feedback oscillator value β new corresponding to above-mentioned equalizer correcting feature γ new that step S102 has obtained, as the feedback oscillator value β that will be stored in afterwards in the parameter storage area 38.

Therefore, in the present embodiment, the feedback oscillator value is provided with recently, and the equalizer correcting feature corresponding to the feedback oscillator value that is provided with recently can be set in addition.In other words, except the feedback oscillator value, can adjust the equalizer correcting feature automatically.

With Fig. 2 and 10 similarly be, in application combination under the situation of configuration of MFB signal processing system of a plurality of feedback control systems 1 to n, at first, as mentioned above, the feedback oscillator value β new (1) when obtaining closed loop for each system is to β new (n).In addition, the equalizer correcting feature is provided with part 37 and calculates by using to each new feedback oscillator value β new (1) that obtains of a plurality of systems carries out to β (n) to the feedback oscillator value β (1) of β new (n) and storage in parameter storage area 38.As result calculated, obtain the correcting value of the sum of errors balancer characteristic of frequency characteristic, and finally obtain equalizer correcting feature γ new.

In addition, about how the equalizer correcting feature be set to transport from factory previous stage initial storage characteristic, for example,, can carry out following process so that accurately be provided with according to the variation of each device.

Figure 14 shows the profile instance corresponding to the MFB signal processing system of the adjustment of initial equalizer correcting feature.In the figure, for example form MFB signal processing system according to closed loop same as shown in Figure 2.In addition, in the outside of digital signal processing unit 10, add microphone 41, amplifier of microphone 42 and ADC43.In addition, digital signal processing unit 10 comprises buffer 44 in addition, FFT part 45, and contrary-TSP processing/feature extraction part 46 and equalizer correcting feature are provided with part 47.

Then,, at first measuring-signal is input to ADC11 for the equalizer correcting feature is set, and operation MFB signal processing system.At this moment, the correcting feature of low-band correction equalizer 12 is set to flat characteristic.In other words, this configuration is identical with the configuration by low-band correction equalizer 12.In addition, adjust the feedback oscillator value of gain controlling part 21 in advance.

Cloth microphone 41 is to receive the sound that reproduces from loudspeaker unit 16.Therefore, can obtain the audio signal that meets the sound that obtains by use loudspeaker unit 16 reproduction measuring-signals by microphone 41.This audio signal is exaggerated by for example amplifier of microphone 42, and is converted into digital signal by ADC 43, so that be input to digital signal processing unit 10.

At digital signal processing unit 10, by the received digital audio and video signals of its sound is passed through buffer 44, FFT processing section 45 and contrary-TSP processing/feature extraction part 46, execution is equal to buffer shown in Figure 12 33, the processing of FFT processing section 34 and contrary-TSP processing/feature extraction part 35 execution.In other words, can obtain the frequency characteristic of the measurement sound that receives by microphone.

The equalizer correcting feature is provided with part 47 and obtains one to be used for contrary-correction of frequency characteristic that TSP processing/feature extraction part 35 is obtained be the correcting value of target frequency characteristic.In other words, the equalizer correcting feature is provided with part 47 and obtains equalizer correcting feature γ.Then, the equalizer correcting feature γ that obtains as mentioned above is stored in the parameter storage area 38 for example shown in Figure 12.

The configuration that present embodiment is not limited to describe up to now.

For example, in the configuration of above-mentioned MFB signal processing system, digital signal is converted into analog signal by DAC14 and is disposed in power amplifier 15 amplifications of inert stage so that drive loudspeaker unit 16.Yet this part can be by the configuration of D class A amplifier A, and this amplifier receives digital audio and video signals as input and driving loudspeaker unit etc.

In addition, as mentioned above, be the feedback method of MFB combination, the type of the transducer of the motion of detection loudspeaker vibrating diaphragm, circuit etc., number of the feedback method that make up or the like is not limited to above-mentioned configuration, but can appropriate change.

The application comprises and the Japanese priority patent application JP2009-140968 disclosed theme relevant theme of on June 12nd, 2009 in the application of Japan Patent office that its full content is incorporated herein by reference at this.

Those skilled in the art should be understood that, various corrections, and combination, sub-portfolio and variation may occur because of design requirement and other factors, as long as they are within the scope of appended claims and equivalent thereof.

Claims

1. signal handling equipment comprises:

One or more checkout gears are arranged to be used for according to detecting the motion of the vibrating membrane of loud speaker as first of different feedback methods to the n feedback method;

Analog-digital commutator, the one or more detection signals that are used for analog form that checkout gear is obtained are converted to digital form;

Feedback signal generating means is used for generating corresponding to first feedback signal to the n feedback method by the detection signal that utilizes the digital form that analog-digital commutator obtains;

Synthesizer is used for being output as the audio signal and the feedback signal combination of digital form of the drive signal of loud speaker;

The correcting balancer device is used to be provided with equalization characteristic, with the frequency characteristic of the audio signal by changing digital form, makes that the sound by loudspeaker reproduction has target frequency characteristic;

The feedback operation setting device is used for from first to the n feedback method feedback method of carrying out the feedback operation of being carried out by synthesizer that audio signal and feedback signal are made up and the feedback method of not carrying out feedback operation being set; And

Equalization characteristic changes and setting device, and being used for will be by the equalization characteristic of correcting balancer device setting according to being changed by the feedback method of the set execution feedback operation of feedback operation setting device and the combination of not carrying out the feedback method of feedback operation.

2. according to the signal handling equipment of claim 1, also comprise:

The measuring-signal generating apparatus is used to generate the measuring-signal of digital form with the drive signal output as loud speaker; The frequency characteristic deriving means, be used for obtaining frequency characteristic by the detection signal that receives each feedback method, described detection signal is obtained by the checkout gear detection when measuring-signal is provided for loud speaker as drive signal and is converted to digital form by analog-digital commutator; And

Gain regulator is used for the frequency characteristic based on the detection signal of each feedback method that is obtained by the frequency characteristic deriving means, for each feedback method obtains the gain that will be provided with by gain control,

Wherein feedback signal generating means comprises gain control, is used to corresponding to first each feedback signal to the n feedback method and applies described gain to the feedback signal of correspondence.

3. according to the signal handling equipment of claim 2, also comprise:

The equalization characteristic adjusting device, be used at least gain based on each the new feedback method that obtains by gain regulator, and the gain that when having obtained gain for each new feedback method, has been provided with for each feedback method, for each the new feedback method corresponding to the time that new gain is set by gain control obtains equalization characteristic.

4. according to the signal handling equipment of claim 2, gain when wherein gain regulator at first obtains feedback signal and is not synthesized the open loop of device combination based on the frequency characteristic of the detection signal that is obtained by the frequency characteristic deriving means, and the gain when obtaining feedback signal and be synthesized the closed loop of device combination by the Calculation of Gain when utilizing open loop, as the gain of each feedback method that is provided with by gain control.

5. according to the signal handling equipment of claim 3, gain when wherein gain regulator at first obtains feedback signal and is not synthesized the open loop of device combination based on the frequency characteristic of the detection signal that is obtained by the frequency characteristic deriving means, and the gain when obtaining feedback signal and be synthesized the closed loop of device combination by the Calculation of Gain when utilizing open loop, as the gain of each feedback method that is provided with by gain control.

6. according to the signal handling equipment of claim 2, also comprise:

Gain changes and setting device, is used for imposing on by gain control change and setting the gain of each feedback signal,

Wherein equalization characteristic change and setting device are according to change and setting to the gain that feedback signal applied corresponding with the feedback method of carrying out feedback operation, and change will be by the equalization characteristic of correcting balancer device setting.

7. according to the signal handling equipment of claim 3, also comprise:

8. according to the signal handling equipment of claim 4, also comprise:

9. according to the signal handling equipment of claim 5, also comprise:

10. signal processing method may further comprise the steps:

Layout is used for being converted to digital form according to the first one or more detection signals that detect the analog form that one or more checkout gears of motion of the vibrating membrane of loud speaker obtain to the n feedback method as different feedback methods;

Generate corresponding to first the feedback signal by utilizing to the n feedback method at the detection signal that one or more detection signals is converted to the digital form of obtaining in the step of digital form;

Will be output as the audio signal of digital form and the feedback signal combination of the drive signal of loud speaker;

Equalization characteristic is set, and the frequency characteristic with the audio signal by changing digital form allows to have target frequency characteristic by the sound of loudspeaker reproduction;

From first the feedback method of carrying out the feedback operation of carrying out that audio signal and feedback signal are made up in the step with audio signal and feedback signal combination and the feedback method of not carrying out feedback operation are set to the n feedback method; And

Change the equalization characteristic that will in the step of equalization characteristic is set, be provided with according to the feedback method of execution feedback operation set in the step of feedback method is set and the combination of not carrying out the feedback method of feedback operation.

11. a signal handling equipment comprises:

One or more detecting units are arranged to be used for according to detecting the motion of the vibrating membrane of loud speaker as first of different feedback methods to the n feedback method;

AD conversion unit, one or more detection signals that configuration is used for the analog form that will be obtained by detecting unit are converted to digital form;

Feedback signal generation unit, configuration are used for generating corresponding to first feedback signal to the n feedback method by the detection signal that utilizes the digital form of being obtained by AD conversion unit;

The audio signal of digital form that synthesis unit, configuration are used for being output as the drive signal of loud speaker makes up with feedback signal;

The correcting balancer unit, configuration is used to be provided with equalization characteristic, and the frequency characteristic with the audio signal by changing digital form allows to have target frequency characteristic by the sound of loudspeaker reproduction;

Feedback operation is provided with the unit, is used for from first to the n feedback method feedback method of carrying out the feedback operation of being carried out by synthesis unit that audio signal and feedback signal are made up and the feedback method of not carrying out feedback operation being set; And

Equalization characteristic changes and the unit is set, and being used for changing according to the combination that by feedback operation the feedback method of the set execution feedback operation in unit is set and does not carry out the feedback method of feedback operation will be by the equalization characteristic of correcting balancer unit setting.